Abstract
Poly[(R)-3-hydroxybutyrare-co-(R)-3-hydroxypivalate] (P(3HB-co-3HPi)) films, a type of polyhydroxyalkanoate (PHA), are oxidized using photoactivated chlorine dioxide radical (ClO(2)•) gas to generate carboxyl groups and loaded with divalent metal cations, including Cu(2+), Zn(2+), and Ca(2+) ions, via ionic interactions. The P(3HB-co-3HPi) films loaded with Cu(2+) ions exhibit enhanced antibacterial activity against Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli) compared with untreated P(3HB-co-3HPi) films. In seawater, the biodegradation of these Cu(2+) and Zn(2+)-loaded films is initially inhibited by the antimicrobial activity of the cations and occurs gradually; therefore, loading antimicrobial divalent metal cations onto the surface of PHAs inhibits biodegradation in seawater temporarily but allows biodegradation to occur with time. These results indicate that PHAs could be employed in seawater without undergoing biodegradation, such that PHAs could be used in fishing gear, including fishing lines that are repeatedly exposed to seawater for short periods.